The advantages of fibre-optic communication systems with high bandwidth capability and link security are recognized. In many such systems, the use of single fibers have a tremendous economic impact for long-distance communications. The development of airborne fibre-optic systems projects applications using a single fibre that can be "payed-out" and establishes two-way communication with an active system. The single fibre is a necessity from the standpoint of pay-out characteristics, payload, and maximization of length. However, to establish this communication, bi-directional couplers that allow simultaneous transmission and reception of the optical signals are required at each end of the transmission fibre.
Therefore, it is an object of this invention to provide a bi-directional coupler for fibre-optic transmission over a single two-way fibre.
Another object of this invention is to provide a bi-directional coupler with good isolation from near-end transmitter crosstalk radiation.
Still another object of this invention is to provide a bi-directional coupler which has capability of high band width and full duplex operation on a single fibre.
Other objects and advantages of this invention will be obvious to those skilled in this art.